Bacterial biofllms: resistance to antimicrobial agents

Gander, Sarah

doi:10.1093/jac/37.6.1047

Cited by 63 publications

(48 citation statements)

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“…It is thought that the formation of the glycocalyx serves as an integral matrix for a biofilm and that following the adhesion of bacteria to a substrate, the glycocalyx forms a protective milieu for cell division and microcolony formation and growth (7,11). Some studies propose that the glycocalyx either acts as a diffusion barrier or, by complexing antibacterial agents, excludes and/or influences the penetration of antimicrobial agents to the underlying cells (10,13). Modern medicine increasingly relies on the use of indwelling medical devices such as catheters and prosthetic joints for multiple purposes.…”

Section: Resultsmentioning

confidence: 99%

Investigating Microbial (Micro)colony Heterogeneity by Vibrational Spectroscopy

Choo-Smith

Maquelin

Vreeswijk

et al. 2001

Appl Environ Microbiol

231

160

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Fourier transform infrared and Raman microspectroscopy are currently being developed as new methods for the rapid identification of clinically relevant microorganisms. These methods involve measuring spectra from microcolonies which have been cultured for as little as 6 h, followed by the nonsubjective identification of microorganisms through the use of multivariate statistical analyses. To examine the biological heterogeneity of microorganism growth which is reflected in the spectra, measurements were acquired from various positions within (micro)colonies cultured for 6, 12, and 24 h. The studies reveal that there is little spectral variance in 6-h microcolonies. In contrast, the 12-and 24-h cultures exhibited a significant amount of heterogeneity. Hierarchical cluster analysis of the spectra from the various positions and depths reveals the presence of different layers in the colonies. Further analysis indicates that spectra acquired from the surface of the colonies exhibit higher levels of glycogen than do the deeper layers of the colony. Additionally, the spectra from the deeper layers present with higher RNA levels than the surface layers. Therefore, the 6-h colonies with their limited heterogeneity are more suitable for inclusion in a spectral database to be used for classification purposes. These results also demonstrate that vibrational spectroscopic techniques can be useful tools for studying the nature of colony development and biofilm formation.In recent years, there has been much effort invested into the development of new techniques for the identification of microorganisms. Many of these methods are aimed at providing the clinician with more rapid identification of the microorganism responsible for infection in order to begin the appropriate course of antimicrobial treatment (1,9,15,21,27,31,44,51). The emergence of these novel methods reflects the rise in drug-resistant microorganisms, which requires that antimicrobial treatment be more effectively managed (2, 12, 28, 52). Among the new methods are those based on vibrational spectroscopic techniques, namely Fourier transform infrared (FT-IR) and Raman spectroscopies. Vibrational spectroscopic methods are reagentless procedures in which there is no need to add dyes or labels for spectral measurement. These nondestructive techniques are based on the absorption (FT-IR) or scattering (Raman) of light directed onto a sample. The amount of light absorbed or scattered depends on the molecules found within the sample and the environment in which these molecules are found. With these highly sensitive techniques, the frequency of light in the resulting spectrum provides biochemical information regarding the molecular composition and molecular structure of and molecular interaction in cells and tissues (24,55). Raman and infrared spectroscopies are complementary techniques which together can provide a more complete impression of the biochemical information within a sample. Furthermore, these two methods differ such that each is capable of providing informatio...

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Section: Resultsmentioning

confidence: 99%

Investigating Microbial (Micro)colony Heterogeneity by Vibrational Spectroscopy

Choo-Smith

Maquelin

Vreeswijk

et al. 2001

Appl Environ Microbiol

231

160

View full text Add to dashboard Cite

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“…Surface association allows the organisms to persist in a favourable environment, while the biofilm structure protects cells from dehydration and other environmental pressures (Donlan & Costerton, 2002). Biofilms can form on almost any biological or abiotic surface and generally have susceptibilities towards antibiotics and biocides that are 100-1000-fold less than equivalent populations of planktonic bacteria (Gander, 1996;Gilbert et al, 2002;O'Toole, 2002). Biofilms have an enormous impact on healthcare, and are estimated to be associated with 65 % of nosocomial infections (Potera, 1999).…”

Section: Introductionmentioning

confidence: 99%

Efficacy of common hospital biocides with biofilms of multi-drug resistant clinical isolates

Smith

Hunter

2008

Journal of Medical Microbiology

215

154

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The hospital environment is particularly susceptible to contamination by bacterial pathogens that grow on surfaces in biofilms. The effects of hospital biocides on two nosocomial pathogens, meticillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, growing as free-floating (planktonic) and adherent biofilm populations (sessile) were examined. Clinical isolates of MRSA and P. aeruginosa were grown as biofilms on discs of materials found in the hospital environment (stainless steel, glass, polyethylene and Teflon) and treated with three commonly used hospital biocides containing benzalkonium chloride (1 % w/v), chlorhexidine gluconate (4 % w/v) and triclosan (1 % w/v). Cell viability following biocide treatment was determined using an XTT assay and the LIVE/DEAD BacLight Bacterial Viability kit. The minimum bactericidal concentration (MBC) of all biocides for planktonic populations of both organisms was considerably less than the concentration recommended for use by the manufacturer. However, when isolates were grown as biofilms, the biocides were ineffective at killing bacteria at the concentrations recommended for use. Following biocide treatment, 0-11 % of cells in MRSA biofilms survived, and up to 80 % of cells in P. aeruginosa biofilms survived. This study suggests that although biocides may be effective against planktonic populations of bacteria, some biocides currently used in hospitals are ineffective against nosocomial pathogens growing as biofilms attached to surfaces and fail to control this reservoir for hospital-acquired infection.

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“…The pathogenesis of P. aeruginosa is mediated by secreted virulence factors, which include toxins, such as pyocyanin, pyoverdine, siderophores, and hydrogen cyanide (12,13), as well as by bacterial enzymes, such as elastase and alkaline protease (14). Moreover, biofilm formation protects the bacteria from adverse environmental factors and increases their antibiotic resistance and pathogenesis (15). Interestingly, the virulence factors and biofilm formation were found to be regulated by quorum centration in each plate to prevent egg hatching.…”

mentioning

confidence: 99%

Components of the Cultivated Red Seaweed Chondrus crispus Enhance the Immune Response of Caenorhabditis elegans to Pseudomonas aeruginosa through the pmk-1 , daf-2/daf-16 , and skn-1 Pathways

Liu

Hafting

Critchley

et al. 2013

Appl Environ Microbiol

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Marine macroalgae are rich in bioactive compounds that can, when consumed, impart beneficial effects on animal and human health. The red seaweed Chondrus crispus has been reported to have a wide range of health-promoting activities, such as antitumor and antiviral activities. Using a Caenorhabditis elegans infection model, we show that C. crispus water extract (CCWE) enhances host immunity and suppresses the expression of quorum sensing (QS) and the virulence factors of Pseudomonas aeruginosa (strain PA14). Supplementation of nematode growth medium with CCWE induced the expression of C. elegans innate immune genes, such as irg-1, irg-2, F49F1.6, hsf-1, K05D8.5, F56D6.2, C29F3.7, F28D1.3, F38A1.5 ZK6.7, lys-1, spp-1, and abf-1, by more than 2-fold, while T20G5.7 was not affected. Additionally, CCWE suppressed the expression of PA14 QS genes and virulence factors, although it did not affect the growth of the bacteria. These effects correlated with a 28% reduction in the PA14-inflicted killing of C. elegans. Kappa-carrageenan (K-CGN), a major component of CCWE, was shown to play an important role in the enhancement of host immunity. Using C. elegans mutants, we identified that pmk-1, daf-2/daf-16, and skn-1 are essential in the K-CGN-induced host immune response. In view of the conservation of innate immune pathways between C. elegans and humans, the results of this study suggest that water-soluble components of C. crispus may also play a health-promoting role in higher animals and humans.

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Bacterial biofllms: resistance to antimicrobial agents

Cited by 63 publications

References 0 publications

Investigating Microbial (Micro)colony Heterogeneity by Vibrational Spectroscopy

Investigating Microbial (Micro)colony Heterogeneity by Vibrational Spectroscopy

Efficacy of common hospital biocides with biofilms of multi-drug resistant clinical isolates

Components of the Cultivated Red Seaweed Chondrus crispus Enhance the Immune Response of Caenorhabditis elegans to Pseudomonas aeruginosa through the pmk-1 , daf-2/daf-16 , and skn-1 Pathways

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